Disc brake issue
 

I have a 4 wheel disc brake conversion on a 70 c20. After pressing the brake pedal and releasing i can't spin wheels freely, especially the fronts. I unbolted the master cylinder and it didn't free up the wheels so it's not the rod length. If I open the bleeders it frees up the wheels but still takes an effort to turn them. M/C is new with a hydroboost .
Any thoughts ?
https://beamingpix.com/images/2025/02/26/1000004193.jpg
https://beamingpix.com/images/2025/02/23/1000004183.jpg

Re: Disc brake issue
 

Does it still have the drum brake residual pressure valves plumbed in the lines? They are basically small check valves in the lines that hold a small amount of pressure on the drum system wheel cylinder to keep the shoes on the drum and minimize brake pedal travel.

Re: Disc brake issue
 

Bad brake hose?

Re: Disc brake issue
 

sub'd

Re: Disc brake issue
 

No. All new stainless lines

Re: Disc brake issue
 

When you open the bleeders on the front does it stream out or just a dribble ? If it streams out then I would think the master is defective since you unbolted it to check the rod and it didn’t help .

Re: Disc brake issue
 

You mentioned new stainless hard lines. What about the hoses as litebulblsc mentioned? Old hoses can look fine on the outside while the inner liner has collapsed acting like a check valve.

Re: Disc brake issue
 

Hardly any fluid comes out

Re: Disc brake issue
 

Then it’s not a hydraulic problem . So it would stand to logic there is a mechanical issue. How long have the calipers been sitting ? May be hanging up .